Mount Teneriffe is the tall peak to the northeast of Mount Si, or the "next one" along the Middle Fork of the Snoqualmie River (there are a couple taller peaks just north of Mount Si; I'm not sure what they are). It stands 4800 feet tall, although its generally obstructed by Mount Si if you're west of it and Mailbox Peak if you're east of it.
There's a couple reasons Teneriffe is not as well known, or hiked, as others in the area. There isn't a good official trail for Teneriffe. The official trail takes you through 7 miles of logging roads, and the unofficial trail takes you on a 3 mile steep hike - so steep that they are currently building an alternate route. And there just isn't good parking. A few cars can fit at the trailhead - but during school days parking is not allowed as this is used as a school bus turnaround.
But that doesn't mean Teneriffe isn't worth doing. The peak is flat, giving a phenomenal 360 degree view of Rainier, Rattlesnake, Mount Si, Adams, the Middle Fork, the upper Snoqualmie Valley, Seattle, the Olympics, and even Bellevue and Tacoma. The views are easily equal those of Mount Washington, possibly better.
I took the Kamikaze trail today, and it was a killer. Similar to Mailbox Peak, its steep and doesn't let up until you get to the top. By my estimates it climbs 3000 feet in about 3 miles. So not as steep as Mailbox, but that didn't make it seem less challenging today.
The trailhead is located a mile past the Mount Si trailhead. Take I-90 to exit 32, head north, then left on North Bend Way. In less than half a mile you'll see the turnoff for Mount Si Road on the right. Follow the road for about 3 miles, you'll see the school bus turnaround on your left. Park your car and head up the logging road.
There are two ways to get to the Kamikaze Trail. About 3/4 mile along the logging road you'll see a trail off to your right. From here it's a 3/4 mile gradual incline before the steep part starts. The second way is to continue along the logging road another 1/4 mile, and off to the right you'll see a path heading up, right along a stream. This stream is fed by Kamikaze Falls. This second way is shorter, but steeper. Both join up just south of the Falls.
I took the longer route. The first major stop along the trail is Kamikaze falls at 2300 feet, about 1/4 mile along the steep part of the trail. When you first see Kamikaze Falls, its impressive enough. But, continue up the trail (literally), and it takes you up the falls to a viewpoint that's basically looking straight up at the falls about 300 feet above you. Today the flow was light, but I imagine in spring you would get drenched.
Once you're done taking in the falls, you still have 2500 feet to go in about 1.5 miles. This stretch rivals Mailbox Peak, although certainly not as long as it. At 2900 feet you will reach a ridge that provides nice views of Snoqualmie Valley, but doesn't let up until you get to the top. The last 100 feet is almost a scramble, but so worth it for the views from the top. Teneriffe peaks at 4800 feet, 500 feet higher than Mount Si's haystack or Mount Washington.
Today was a beautiful day, and I was surprised I could see all the way to Tacoma. Also, I spotted both Seattle and Bellevue, surprising as I expected Mount Si to block the view.
I've read many people take the logging road back down. Given that it was 7 miles, I took my chances on the steep descent. It was tiring, but not as dangerous or risky as I expected.
It took me 3 hours to get to the top, and another 2 hours to get down, so a 5 hour hike with 4000 feet of elevation gain and six miles of hiking round trip. I only saw 5 other people today on the trail. Just the way I like it.
Kamikaze Falls. I am shooting almost straight up on this shot.
Snoqualmie Valley / South Fork / I-90. Mailbox Peak is on the left, Mount Washington lies there just "below" Rainier.
Seattle, just above Mount Si
Obligatory Rainier shot, with Mount Washington in the foreground.